1. Technical Field of the Invention
The present invention relates to an audio signal processing apparatus having functions to assign channels to controls provided on a manipulation panel, and relates to set and change values of parameters of the assigned channels through manipulation of the controls.
2. Description of the Related Art
There is known an audio signal processing apparatus which includes a plurality of channel strips, each having controls such as a fader, a rotary encoder, and various buttons, and which assigns input channels to the channel strips and allows the user to adjust the values of various parameters of an input channel through controls on a channel strip corresponding to the input channel. For example, the following Non-Patent Reference 1 (see Section 4 “Basic Operation of Input Channel”) describes, on pages 32 and 33, a console of an audio mixing system in which layer data is assigned to each “channel strip portion” which is an array of channel strips and the assigned layer data is switched to make it possible to control many channels using a limited number of channel strips. The term “layer data” refers to data defined to specify channels (assignment channels) which are to be assigned to channel strips included in a channel strip portion (channel strip array).
Patent Reference 1 describes a mixer that allows a user to create user layer data separately from default layer data provided by the manufacturer. That is, the mixer allows the user to specify channels (assignment channels) assigned to channel strips included in a channel strip portion to create a piece of user layer data. Channel strips, for which assignment channels are not specified but instead “current state maintained” is specified, may be set in the user layer data. For example, when the layer data calling state has been switched from the calling state of first layer data to that of second layer data (which is referred to as user layer data), previous assignment channels of the first layer data remain unchanged for each channel strip for which “current state maintained” is specified in the second layer data.
A function to group and control a plurality of desired input channels is described in Non-Patent References 1 and 2. For example, a plurality of input channels may be assigned to a “DCA group”, and the levels of the input channels may then be collectively adjusted using a DCA fader while maintaining level differences of the input channels, or a plurality of input channels may be assigned to a “mute group” and mute of the input channels may then be collectively turned on/off by turning a specific key on/off (see Section 7 “DCA Group” on pages 92 to 98 of Non-Patent Reference 1 and Section 11 “Grouping/Link” on pages 100 to 119 of Non-Patent Reference 2). A channel link function, which links desired parameters of a plurality of input channels belonging to a group, is described on pages 120 and 121 of Non-Patent Reference 2.
Although the function, which enables a plurality of channels to be grouped into a group and to be collectively manipulated using one control as described above, is convenient, users may also desire to individually manipulate the plurality of channels of the group. Thus, a digital mixer is provided, which allows a group to be expanded into individual channels to be assigned to a channel strip portion through specific manipulation. In this digital mixer, when a button of a desired group is depressed, individual input channels of the group are sequentially assigned to channel strips, allowing the user to individually manipulate the input channels.    [Patent Reference 1] Japanese Patent Application Publication No. 2008-227761